package main

import (
	"fmt"
	"strings"
)

type product struct {
	id   int
	name string
}

type user struct {
	username string
	password string
}

func main() {
	var products []product
	var users []user
	var isLogin = false
	var input int

	for !isLogin {
		fmt.Println("Welcome to our program.")
		fmt.Println("List actions:")
		fmt.Println("1. Login")
		fmt.Println("2. Register")
		fmt.Println("0. Cancel")

		action := 0
		_, _ = fmt.Scanf("%d", &action)

		if action == 1 {
			isLogin = login(users)
		} else if action == 2 {
			username := ""
			password := ""
			fmt.Println("Masukkan username:")
			_, _ = fmt.Scanf("%s", &username)
			fmt.Println("Masukkan password:")
			_, _ = fmt.Scanf("%s", &password)
			register(username, password, &users)
		} else if action == 0 {
			break
		}
	}

	for isLogin {
		fmt.Println("[======================]")
		fmt.Println("List menu: ")
		fmt.Println("1.] -> Show list product")
		fmt.Println("2.] -> Show product by id")
		fmt.Println("3.] -> Add product")
		fmt.Println("4.] -> Update product")
		fmt.Println("5.] -> Delete product")
		fmt.Println("0.] -> [[ Exit Program ]]")
		fmt.Println("[======================]")

		_, _ = fmt.Scanf("%d", &input)

		switch input {
		case 0:
			fmt.Println("Thank you for using our program! :)")
			isLogin = false
			break
		case 1:
			showListProduct(products)
			break
		case 2:
			id := 0
			fmt.Println("Masukkan id product:")
			_, _ = fmt.Scanf("%d", &id)
			showProductById(id, products)
			break
		case 3:
			//Kita akan melakukan perubahan terhadap products dengan menambahkan data produk, sehingga kita perlu menggunakan pointer
			//Kirimkan alamat array products (dalam memory dengan &products) kepada method addProduct(_)
			addProduct(&products)
			break
		case 4:
			//Kita akan melakukan perubahan terhadap products dengan mengubah data product, sehingga kita perlu menggunakan pointer
			//Kirimkan alamat array products (dalam memory dengan &products) kepada method addProduct(_)
			id := 0
			fmt.Println("Masukkan id product:")
			_, _ = fmt.Scanf("%d", &id)
			updateProductById(id, &products)
			break
		case 5:
			//Kita akan melakukan perubahan terhadap products dengan menghapus data product dari products, sehingga kita perlu menggunakan pointer
			//Kirimkan id product yang ingin dihapus dan alamat array products (dalam memory dengan &products) kepada method addProduct(_)
			id := 0
			fmt.Println("Masukkan id product:")
			_, _ = fmt.Scanf("%d", &id)
			deleteProductById(id, &products)
			break
		default:
			fmt.Println("Menu tidak dikenali, coba cek lagi!")
			break
		}
	}
}

func deleteProductById(id int, products *[]product) {
	for i, p := range *products {
		if p.id == id {
			*products = append((*products)[:i], (*products)[i+1:]...)
		}
	}
}

func updateProductById(id int, products *[]product) {
	newName := ""

	fmt.Println("Masukkan nama terbaru product")
	_, _ = fmt.Scanf("%s", &newName)

	for i, p := range *products {
		if p.id == id {
			(*products)[i] = product{id, newName}
		}
	}
}

func addProduct(products *[]product) {
	id := 0
	name := ""
	fmt.Println("Masukkan id product")
	_, _ = fmt.Scanf("%d", &id)
	fmt.Println("Masukkan nama product")
	_, _ = fmt.Scanf("%s", &name)

	product_ := product{id, name}

	*products = append(*products, product_)
}

func showProductById(id int, products []product) {
	for _, p := range products {
		if p.id == id {
			fmt.Println("ID: ", p.id)
			fmt.Println("Name: ", p.name)
			fmt.Println()
		}
	}
}

func showListProduct(products []product) {
	// Untuk setiap product p dengan index i pada array products
	for _, p := range products {
		fmt.Println("ID: ", p.id)
		fmt.Println("Name: ", p.name)
		fmt.Println()
	}
}

//Username: user; Password: pass
func checkCredential(username string, password string, users []user) bool {
	for _, u := range users {
		if strings.Compare(username, u.username) == 0 && strings.Compare(password, u.password) == 0 {
			return true
		}
	}

	return false
}

func login(users []user) bool {
	var username string
	var password string

	fmt.Println("You need to login to access this program.")

	fmt.Println("Username: ")
	_, _ = fmt.Scanf("%s", &username)
	fmt.Println("Password: ")
	_, _ = fmt.Scanf("%s", &password)

	if checkCredential(username, password, users) {
		return true
	}

	return false
}

func register(username string, password string, users *[]user) {
	*users = append(*users, user{username, password})
}